Influence of Growth Rate on the Solute Distribution of Directionally Solidified Cu-Ag-Zr Alloy

2011 ◽  
Vol 275 ◽  
pp. 192-195
Author(s):  
Bok Hyun Kang ◽  
Woo Hyun Lee ◽  
Ki Young Kim ◽  
Hoon Cho ◽  
Jae Soo Noh
Keyword(s):  
Electrical Conductivity ◽  
Growth Rate ◽  
Temperature Gradient ◽  
Constant Temperature ◽  
Vickers Hardness ◽  
Growth Rates ◽  
Back Diffusion ◽  
Directionally Solidified ◽  
Constant Temperature Gradient ◽  
Zr Alloy

Cu-2wt.Ag-2wt.%Zr alloy was directionally solidified with different growth rates(V=10-200 um/s) at a constant temperature gradient(G=3.1 K/mm) in a modified Bridgman furnace. The influence of growth rate was investigated by observing the microstructure and measuring the solutes’ compositions within the Cu-matrix and dendrite boundaries. The experimental results show that increasing the growth rate, decreased both the primary and secondary arm spacing and increased micro-Vickers hardness. The solutes’ concentration also increased as a result of the back diffusion caused by a decreasing growth rate. The electrical conductivity depends on the solutes’ distribution.

INFLUENCE OF GROWTH RATE ON MICROSTRUCTURE AND MICROINDENTATION HARDNESS OF DIRECTIONALLY SOLIDIFIED TIN–CADMIUM EUTECTIC ALLOY

2009 ◽  
Vol 16 (02) ◽  
pp. 191-201 ◽  
Author(s):  
E. ÇADIRLI ◽  
H. KAYA ◽  
M. GÜNDÜZ
Keyword(s):  
Growth Rate ◽  
Temperature Gradient ◽  
Directional Solidification ◽  
Constant Temperature ◽  
Eutectic Alloy ◽  
Directionally Solidified ◽  
Constant Temperature Gradient ◽  
Microindentation Hardness ◽  
Solidification Furnace ◽  
Eutectic Melt

Sn – Cd eutectic melt was first obtained in a hot filling furnace and then directionally solidified upward with different growth rate ranges (8.1–165 μm/s) at a constant temperature gradient G (4.35 K/mm) in the Bridgman-type directional solidification furnace. The lamellar spacings (λ) were measured from both transverse and longitudinal sections of the samples. The influence of the growth rate (V) on lamellar spacings (λ) and undercoolings (Δ T) was analyzed. λ2V, ΔTλ and ΔTV-0.5 values were determined by using λ,ΔT and V values. Microindentation hardness (HV) was measured from both transverse and longitudinal sections of the specimens. HV values increase with the increasing values of V but decrease with increasing λ values. λ-V, λ - ΔT and λ2V results have been compared with the Jackson–Hunt eutectic model and similar experimental results, HV - V and HV - λ results were also compared with the previous work.

Morphological Characteristics of W-Nanowires after Selective Etching

2014 ◽  
Vol 1004-1005 ◽  
pp. 24-27
Author(s):  
Wen Jia Wang ◽  
Zhi Long Zhao ◽  
Ming Tang ◽  
Jian Jun Gao
Keyword(s):  
Growth Rate ◽  
Temperature Gradient ◽  
Directional Solidification ◽  
Morphological Characteristics ◽  
Selective Dissolution ◽  
Stability Diagram ◽  
Selective Etching ◽  
Directionally Solidified ◽  
Solidification Furnace ◽  
Nial Matrix

An eutectic NiAl–1.5 at.% W alloy prepared by using directionally solidified (DS)was employed as a source for producing W-nanowires. Several growth rate of 8,15,25/s was respectively used at a temperature gradient of ~240 K/cm in a Bridgman-type directional solidification furnace. A combined stability diagram was applied to predict proper conditions for the selective dissolution of NiAl matrix to get W-wires. Etching in a mixture of HCl:H2O2released parallel aligned W-nanowires with a wire diameter of ~500 nm. Different morphologies, such as nanobelts, lotus-shaped, conical of W-nanowires are obtained at the different conditions.

Effects of Growth Rates on Directionally Solidified Microstructure of Al-Ni-Y Ternary Alloy

2012 ◽  
Vol 562-564 ◽  
pp. 477-481
Author(s):  
Rui Xu
Keyword(s):  
Temperature Gradient ◽  
Directional Solidification ◽  
Ternary Alloy ◽  
Growth Rates ◽  
Optical Microscope ◽  
Experimental Results ◽  
Al Alloy ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
X Ray

The directional solidification of the ternary Al alloy with composition of 2.6 at%Ni, 0.9 at%Y and 96.5 at% Al was carried out under the temperature gradient of 5 K/mm and the droping velocities of 0.5 mm/min, 1 mm/min, 5 mm/min, 10 mm/min, and 25 mm/min. The microstructure of the Al-Ni-Y ternary alloy was also analyzed by X-ray diffraction and optical microscope. The experimental results show that the microstructures of the Al-Ni-Y ternary alloy are consisted of ª-Al2, Al3Ni and Y4Ni6Al23phase when the alloy was directionally solidified in all directionally solidified rates in the experiments. No primary -Al can be found in the sample with directionally solidified rate of 0.5 mm/min. When the rates higher than 1 mm/min, the primary ª-Al can be observed. The microstructure of the directionally solidified alloy becomes finer and the primary ª-Al is smaller gradually with the increasing of growth velocities when the dropping rate of directional solidification is higher than 5 min/min. Two eutectic structures, Y4Ni6Al23andª-Al eutectic and Al3Ni and ª-Al eutectic, can be found when the dropping rate is higher than 10 mm/min.

Effect of Temperature on Growth of Five Subtropical Grasses. I. Effect of Day and Night Temperature on Growth and Morphological Development

1978 ◽  
Vol 5 (2) ◽  
pp. 131 ◽  
Author(s):  
DA Ivory ◽  
PC Whiteman
Keyword(s):  
Growth Rate ◽  
Diurnal Variation ◽  
Constant Temperature ◽  
Growth Rates ◽  
Leaf Growth ◽  
Maximum Growth ◽  
Effect Of Temperature ◽  
Panicum Maximum ◽  
Morphological Development ◽  
Night Temperature

Cenchrus ciliaris, Chloris gayana, Panicum maximum var, trichoglume, Panicum coloratum var. makarikariense and Pennisetum clandestinum were grown in two experiments in controlled environments, each experiment having all possible day/night temperature combinations of (1) 10, 20, 30, and 40°C and (2) 15,25, 30 and 35°C. Both day and night temperatures significantly affected growth in all species. Growth was greatly restricted by constant temperatures of 10 and 15°, while maximum growth rates occurred at 29-35°C day temperatures with 26-30°C night temperatures. At optimum or supra-optimum temperatures a diurnal variation in temperature gave higher growth rates than a constant temperature for the same daily mean. By contrast, at suboptimum temperatures a constant temperature gave the highest growth rates and growth rate was decreased as the diurnal variation about a given daily mean temperature was increased. Mathematical functions relating the growth of each species to day and night temperature and maximum growth rate at optimum temperatures were developed. The effect of temperature on relative growth rate (Rw) was mediated through its effect on net assimilation rate (EA). Night temperature was found to affect Rw and EA independently of day temperature and therefore a prehistory effect of night temperature on photosynthesis in the subsequent day was indicated. Temperature had significant effects on tillering in P. maximum and P. clandestinum but had little effect in C. gayana, C. ciliaris and P. coloratum. The optimum temperatures for leaf growth and leaf area development in C. ciliaris and C. gayana were higher than the optimum temperatures for growth of the whole plant, while optimum temperatures for stem growth were lower. In P. maximum, P. coloratum and P. clandestinum, optimum temperatures for all growth components were similar. Differences between temperate and tropical grasses in morphological reaction to temperature are discussed.

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